Esophageal disorders are common in diabetes mellitus (DM) patients. DM induces mechanostructural remodeling in the esophagus of humans and animal models. The remodeling is related to esophageal sensorimotor abnormalities and to symptoms frequently encountered by DM patients. For example, gastroesophageal reflux disease (GERD) is a common disorder associated with DM. This review addresses diabetic remodeling of esophageal properties and function in light of the Esophagiome, a scientifically based modeling effort to describe the physiological dynamics of the normal, intact esophagus built upon interdisciplinary approaches with applications for esophageal disease. Unraveling the structural, biomechanical, and sensory remodeling of the esophagus in DM must be based on a multidisciplinary approach that can bridge the knowledge from a variety of scientific disciplines. The first focus of this review is DM-induced morphodynamic and biomechanical remodeling in the esophagus. Second, we review the sensorimotor dysfunction in DM and how it relates to esophageal remodeling. Finally, we discuss the clinical consequences of DM-induced esophageal remodeling, especially in relation to GERD. The ultimate aim is to increase the understanding of DM-induced remodeling of esophageal structure and sensorimotor function in order to assist clinicians to better understand the esophageal disorders induced by DM and to develop better treatments for those patients.

No specific treatment for oropharyngeal dysphagia related to diabetic neuropathy has been described to date. Chemical myotomy of the cricopharyngeus (CP) muscle by botulinum neurotoxin type A (BoNT/A) has been effective in reducing or abolishing dysphagia associated with upper esophageal sphincter (UES) hyperactivity of different etiologies. In the present study, we evaluated the efficacy of BoNT/A injections into the CP muscle in diabetic patients with severe oropharyngeal dysphagia associated with diabetic autonomic and/or somatic peripheral neuropathy.

Twelve type 2 diabetic patients with severe dysphagia for both solid and liquid foods associated with autonomic and/or peripheral somatic neuropathy were investigated. Swallowing function was evaluated by clinical examination, videofluoroscopy, and simultaneous needle electromyography (EMG) of the CP and pharyngeal inferior constrictor (IC) muscles. Clinical evaluation using a four-level dysphagia severity score was performed every other day for the 1st week and thereafter every other week until week 24. Videofluoroscopy and EMG follow-up were carried out at week 1, 4, 12, 16, 18, and 24 after BoNT/A injection. BoNT/A was injected percutaneously into the CP muscle under EMG control.

BoNT/A induced the complete recovery of dysphagia in 10 patients and had a significant (P = 0.0001, ANOVA) improvement in 2 patients within 4 +/- 1.1 days (range 3-7). Clinical improvement was confirmed by videofluoroscopy and EMG.

Our findings suggest a potential benefit from BoNT/A treatment in dysphagia associated with diabetic neuropathy. Randomized controlled trials are needed to confirm this observation.

The relationship between cardiovascular autonomic neuropathy (CVAN) and oesophageal dysfunction in diabetes mellitus has not been well established because reports are contradictory. The aim of this study was to assess oesophageal function and its correlation with CVAN in type 1 diabetic patients without oesophageal symptoms. Forty-six type 1 diabetic patients without oesophageal symptoms (DG) and 34 healthy volunteers (CG) were studied. Both groups underwent CVAN tests and oesophageal manometry and pH-metry. Differences between groups regarding results of cardiovascular autonomic tests and oesophageal studies were statistically analysed. Compared with the CG, the DG group showed insufficient lower oesophageal sphincter (LOS) relaxation and a higher percentage of simultaneous waves (P < 0.01). Patients with CVAN (n = 22) showed a higher prevalence of pathological simultaneous contractions (>10%), and the prevalence of simultaneous waves related to the degree of autonomic neuropathy was: 9% of patients without CVAN, 7% of those suspected to have it and 50% of patients with CVAN (P < 0.001). Factors associated with the presence of pathological simultaneous waves (>10%) were the presence of CVAN and duration of diabetes (P < 0.05, logistic regression analysis). Increase in simultaneous waves and impaired relaxation of LOS are more frequent in diabetic patients with CVAN.

The pathogenetic mechanisms causing esophageal dysmotility is not well understood. We examined 13 patients with solid bolus dysphagia in a radiologic barium study including the swallowing of a 14-mm tablet. In all 13 patients the tablet was caught in the proximal or midesophagus. In 8 patients, the entrapment was associated with symptoms (Group 1) whereas in 5 patients (Group 2), no symptoms were reported. All 13 patients together with a control group of 56 healthy, nondysphagic subjects were tested for autonomic nerve function. Autonomic nerve function tests included registration of electrocardiographic R-R interval variation during deep breathing test (E/I ratio), a test of parasympathetic, vagal, nerve function. The results showed that the E/I ratio was significantly lower in patients with symptoms of bolus-specific esophageal dysmotility (-2,19 [1.76]) (median [interquartile range]) compared with patients without symptoms (0.05 [2, 87], p = 0.0192) and controls (-0.25 [1.26], p = 0.0009). In conclusion, symptomatic bolus-specific esophageal dysmotility is associated with vagal nerve dysfunction.